As the amount of worldwide electrical power consumption has been constantly increasing, power supplies and power converters have become increasingly important in our society. A circuit schematic of the primary elements of a boost-mode DC-to-DC power converter (herein a “boost converter”) is shown in FIG. 1. The boost converter circuit includes inductors 10 and 14, a switching device, i.e., a transistor 11, a rectifying device, i.e., a diode 12, and charge storage devices, i.e., capacitors 13 and 15. During the time that the transistor 11 is ON, the inductor 10 sustains the entire input voltage, and the input current flows through the inductor 10 and the transistor 11, while the electric energy is stored as magnetic energy in the inductor 10. At the same time, the diode 12 prevents the capacitor 13 from discharging through the transistor 11. When the transistor 11 is OFF, the potential across the inductor 10 is reversed and the input current flowing through the inductor 10 also flows through the diode 12, thereby charging the capacitor 13 and supplying energy to the output load at a higher voltage potential than that at the input line.
To date, the diodes and transistors used in power circuits such as the boost converter circuit of FIG. 1 have typically been fabricated with silicon (Si) semiconductor materials. Common diode and transistor devices for power applications include Silicon (Si) Schottky diodes, Si Power MOSFETs such as CoolMOS, and Si Insulated Gate Bipolar Transistors (IGBTs). While Si power devices are inexpensive, they suffer from a number of disadvantages, including relatively low switching speeds and high levels of electrical noise, commonly referred to as electro-magnetic interference or EMI. There has been a consistent trend to increase switching frequencies for more compact power supplies, which requires that the devices used in the power supply have higher switching speeds and that circuit architecture be improved to adequately suppress increased electrical noise resulting from higher frequency of operation. Recently, silicon carbide (SiC) power devices have been researched due to their superior electrical and thermal properties as compared to Si devices. III-Nitride (III-N) based semiconductor devices are now also emerging as attractive candidates for power circuit applications.
While the use of III-N devices has shown to be beneficial in power applications, further improvements may be necessary to adequately suppress EMI while simultaneously maintaining a high efficiency as circuit switching frequencies and switching speeds are further increased.